They Bite (1996)

The plot is basically a cheap ripoff of Humanoids From The Deep, but with Ron Jeremy. Really he's in this! Anyway, there's a film crew trying to make a high concept porno about fish monsters raping women, and it turns out that the little sea-side town that they go to shoot in really does have fish monsters that rape women. There's also a bitchy ichthyologist with the same name as the porn director and some convoluted side plot about aliens.